It takes 3hours to make QT ref

Hi everybody, i'm using fcp 7. I've got apple pro res 422 LT clips. The sequence is set in the right format, but when i want to make a qt ref (of a sequence of 2hours whitout audio) it takes me 3 hours!!
I suppose that the clips in reality are not apple pro res 422, but MPEG-4: this is what MediaHUD told me about the clip.
General
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt
Writing application : Lavf55.12.102
Writing library : Apple QuickTime
Video
ID : 4
Format : ProRes
Format version : Version 0
Format profile : LT
Codec ID : apcs
Bit rate mode : Variable
Bit rate : 109 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:2
The laboratory that gave me the files told that it's impossible: the clips are Apple pro res 422, in effect final cut read them as apple pro res 422 LT!
So? what do I have to think???
Thank a lot for helping me!

You need to ask this on a forum dedicated to FCP7. Try here www.fcp.co/forum/5-final-cut-pro-7-fcp7

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